光皮桦杉木混交林养分利用效率研究

Study on Nutrient Use Efficiency in the Mixed Forest with Betula luminifera and Cunninghamia lanceolata

以福建省三明市郊国有林场的光皮桦、杉木为研究对象,探讨了纯林和混交林成熟叶与衰老叶中的养分状况、氮磷比、养分内转移率以及它们之间的关系。结果表明,叶片中的养分浓度和内转移率一般表现为纯林高于混交林,这是由于混交林改善了立地条件,林木能够从土壤中吸收较多的养分,从而降低了二者叶片中的养分内转移效率。各林分类型成熟叶片中的氮磷比都大于18,表明这些立地条件都存在不同程度的P限制,导致林分叶片PRE大于NRE,衰老叶中的氮磷比大于成熟叶。

Nitrogen and phosphorus concentrations, N：P ratio, nutrient retranslocatlon elnclency oi mature anu senescent leaves in pure and mixed protection forest of Betula luminifera and Cunninghamia lanceolata were discussed in this paper. The results showed that nutrient concentrations and retranslocation efficiency of leaves were higher in pure forest than that in mixed forest, this indicated that soil nutrient availability increased in mixed forest, so the trees could absorb more nutrients from soil and depended less on nutrient retranslocation from senescent leaves. The N：P ratios of mature leaves were all above 18, the limit of nitrogen was less than that of phosphorus, and phosphorus retranslocation efficiency （PRE） was higher than nitrogen retranslocation efficiency （NRE）.